JPS6243915Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an adjustment mechanism that adjusts only the spring characteristics of a coil spring of a front fork that suspends between the front part of a vehicle body such as a two-wheeled vehicle and a front wheel axle.

The mechanism for adjusting the spring characteristics of the coil spring stretched on the front fork is to adjust the position of the spring holder that receives the upper end of the coil spring fitted in the inner cylinder relative to the adjustment member with cam surfaces of different depths. It is known that the set load of the spring is adjusted by changing the set load of the spring.

However, with such a mechanism, there are restrictions on the adjustment range, and the adjustment work requires a lot of effort.
It was accompanied by great difficulties.

The inventors of the present invention have devised this invention in order to eliminate such inconveniences.The purpose of this invention is to adjust the coil springs by adjusting them from the outside, especially in front forks that are filled with oil and gas. To provide a coil spring characteristic adjustment mechanism for a front fork, which allows only the set length of the coil spring to be changed, thereby arbitrarily adjusting only the spring characteristics of the coil spring without affecting the gas spring characteristics. .

In order to achieve such an object, the present invention includes a cylinder whose upper end is fixed to a fork bolt screwed onto the upper end of an inner cylinder and which extends downward, and a shaft part which is rotatably inserted into the fork bolt and faces into the cylinder. An adjusting rod having a thread carved on its outer periphery, a piston that is screwed onto the adjusting rod and whose outer periphery fits into the cylinder, and a cylindrical plunger that integrally extends downward from the piston. The adjustment mechanism is composed of a bottom plate that fits around the outer circumference of the plunger and is fixed to the lower end of the cylinder, and a spring receiver that is fixed to the lower end of the plunger and receives the upper end of the coil spring on its lower surface.

A preferred embodiment of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a longitudinal sectional side view of a front fork provided with an adjustment mechanism according to the present invention, and FIG. 2 is an enlarged longitudinal sectional side view of the upper part of the front fork.

In the front fork 1 shown in FIG.
is an outer cylinder, and an inner cylinder 3 is slidably inserted and fitted into the outer cylinder 2 from above. A guide bush 4 and an oil seal 5 that slide on the outer periphery of the inner cylinder 3 are fitted on the inner periphery of the upper end of the outer cylinder 2.
The open upper end of the inner cylinder 3 is similarly closed by a dust seal 6 that slides on the outer periphery of the inner cylinder 3.

On the other hand, a seat pipe 7 is installed at the inner bottom of the outer cylinder 2 as shown in the figure, and the enlarged diameter tip 7a of the seat pipe 7 is in sliding contact with the inner peripheral part of the inner cylinder 3.

A valve mechanism 8 that slides on the outer periphery of the seat pipe 7 and generates a damping force is fitted into the lower inner periphery of the inner cylinder 3, and the upper end of the inner cylinder 3 is fitted with a fork bolt 9 screwed onto the valve mechanism 8. It's blocked. In addition, 10 in the figure is a rebound spring.

A coil spring adjustment mechanism 20, which is shown in detail in FIG. 2, is provided inside and above the inner cylinder 3.

That is, as shown in FIG. 2, the upper end of a cylinder 21 is fixed to the outer periphery of the lower end of the fork bolt 9, and the cylinder 21 extends downward concentrically with respect to the inner cylinder 3. A bottom plate 22 is fixed to the. Incidentally, a plurality of ventilation holes 21a are bored in the side wall of the cylinder 21.

In addition, there is an adjustment rod 23 in the center of the fork bolt 9.
is rotatably inserted through the rod 23, and the rod 23 is positioned by a stopper ring 24.
A screw 23a is carved on the outer periphery of the shaft portion of the lower half portion facing into the cylinder 21 of No. 3. As shown in the figure, a piston 25 is fitted onto the screw 23a of the adjustment rod 23 so as to be vertically slidable on the inner periphery of the cylinder 21. Further, the upper end of a cylindrical plunger 26 is fixed to the lower surface of the piston 25, and the plunger 26 extends downward through the center of the bottom plate 22, and a disc-shaped spring is attached to the lower end of the plunger 26. A receiver 27 is fixed. An oil hole 27a is bored in the spring receiver 27, and a coil spring 28 is inserted between the spring receiver 27 and the seat pipe 7.
is strung up.

The insertion and fitting of the plunger 26 into the bottom plate 22 is prevented from rotating by any means, so that the plunger 26 and the piston 25 are prevented from rotating, and these 25 and 26 are only allowed to move up and down. It will be done.

Hydraulic oil 30 is filled inside the front fork 1 up to the position shown in the figure, and a chamber S above this is filled.
constitutes a gas chamber, and a stable inert gas such as air is sealed in the gas chamber S.

In the front fork 1 described above, the upper end of the inner cylinder 3 is connected to, for example, the front part of the vehicle body of a motorcycle, and the lower end of the outer cylinder 2 is connected to the front wheel axle.
3 performs relative expansion and contraction.

Due to the relative expansion and contraction movement of the inner and outer cylinders 3 and 2, the hydraulic oil 30 sealed inside flows, and due to the flow resistance when this oil passes through the valve mechanism 8, the required damping force is applied to the front fork 1. occurs. At the same time, the volume inside the front fork 1 increases or decreases, but this increase or decrease is compensated for by compression and expansion of the gas in the gas chamber S, and the gas chamber S is expanded by the coil spring 2.
Together with 8, it functions as a cushion spring and effectively cushions external shocks.

By the way, if the adjustment rod 23 is turned from the outside, the piston 25 that is screwed into it will be connected to the cylinder 21.
The vertical movement of the piston 25 causes the plunger 26 and spring receiver 2 fixed thereto to move up and down.
7 also moves up and down together. The vertical movement of the spring receiver 27 causes the coil spring 28 to expand and contract, and the spring characteristics of the coil spring 28 can be adjusted as desired by external operation.

Then, if we ignore the small volume of plunger 26 entering below the oil surface or the volume of exiting from the oil surface,
The oil level does not change due to the vertical movement of the plunger 26 and the spring receiver 27, and therefore the coil spring 28 can be adjusted independently without affecting the gas spring characteristics of the gas chamber S. Adjustment can be easily performed without requiring any effort.

As is clear from the above explanation, according to the present invention, by rotating the adjustment rod from the outside, the piston that screws onto it, the plunger fixed to it, and the spring receiver are moved up and down as a unit without changing the volume of the gas chamber, and only the set length of the coil spring is changed, so that the spring characteristics of the coil spring alone can be easily and arbitrarily adjusted without affecting the gas spring characteristics.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a vertical sectional side view of a front fork provided with an adjustment mechanism according to the present invention, and FIG. 2 is an enlarged vertical sectional side view of the upper part of the front fork. In the drawing, 2 is an outer cylinder, 3 is an inner cylinder, 7 is a seat pipe, 9 is a fork bolt, 20 is a coil spring adjustment mechanism, 21 is a cylinder, 22 is a bottom plate, 23
is an adjustment rod, 25 is a piston, 26 is a plunger, 27 is a spring holder, 28 is a coil spring, S
is a gas chamber.

Claims (1)

[Scope of utility model registration request] The front fork consists of an inner tube and an outer tube that are slidably fitted together, a coil spring stretched between the upper end of a sheet pipe planted at the bottom of the outer tube, and the inner tube, and oil and gas sealed inside. The attached mechanism includes a cylinder whose upper end is fixed to a fork bolt screwed onto the upper end of the inner cylinder, and which extends downward, and which is rotatably inserted into the fork bolt and has a screw attached to the outer periphery of the shaft facing into the cylinder. a piston that is screwed onto the adjustment rod and whose outer periphery fits into the cylinder; a cylindrical plunger that integrally extends downward from the piston; A coil spring characteristic adjustment mechanism for a front fork, comprising a bottom plate that fits on the outer periphery and is fixed to the lower end of the cylinder, and a spring receiver that is fixed to the lower end of the plunger and receives the upper end of the coil spring on the lower surface. .